A PDU is composed of protocol specific control information and user data
Protocol data units for the Internet protocol suite are:
The transport layer PDU is the TCP segment for
→TCP, and the datagram for UDP.
→The Internet layer PDU is the packet.
→The link layer PDU is the frame.
Which of the following statements are true ?
(a) Advanced Mobile Phone System (AMPS) is a second generation cellular phone system.
(b) IS - 95 is a second generation cellular phone system based on CDMA and DSSS.
(c) The Third generation cellular phone system will provide universal personnel communication.
(a) and (b) only
(b) and (c) only
(a), (b) and (c)
(a) and (c) only
AMPS is a first-generation cellular technology that uses separate frequencies, or "channels", for each conversation (see frequency-division multiple access (FDMA)). It therefore required considerable bandwidth for a large number of users. In general terms, AMPS was very similar to the older "0G" Improved Mobile Telephone Service, but used considerably more computing power in order to select frequencies, hand off conversations to PSTN lines, and handle billing and call setup.
IS - 95 is a second generation cellular phone system based on CDMA and DSSS.
The Third generation cellular phone system will provide universal personnel communication.
Consider ISO-OSI network architecture reference model. Session layer of this model offer Dialog control, token management and ____________ as services.
→ Dialog control: The session layer allows two systems to enter into a dialog. It allows the communication between two processes to take place in either half-duplex (one way at a time) or full-duplex (two ways at a time) mode.
→ Synchronization: The session layer allows a process to add checkpoints, or synchronization points, to a stream of data. For example, if a system is sending a file of 2000 pages, it is advisable to insert checkpoints after every 100 pages to ensure that each 100-page unit is received and acknowledged independently. In this case, if a crash happens during the transmission of page 523, the only pages that need to be reset after system recovery are pages 501 to 523. Pages previous to 501 need not be resent.
Data link layer
Both (A) and (B)
● Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction.
● Physical layer in the OSI model plays the role of interacting with actual hardware and signaling mechanism
Transport, session, presentation, application
Session, presentation, application
Datalink, transport, presentation, application
Physical, datalink, network, transport
Chose the option which matches each element of LIST-1 with exactly one element of LIST-2:
(i)-(d), (ii)-(c), (iii)-(b), (iv)-(a)
(i)-(b), (ii)-(a), (iii)-(d), (iv)-(c)
(i)-(a), (ii)-(d), (iii)-(c), (iv)-(b)
(i)-(d), (ii)-(b), (iii)-(c), (iv)-(a)
2. Gateway→ All seven layers: A gateway, as the name suggests, is a passage to connect two networks together that may work upon different networking models. They basically works as the messenger agents that take data from one system, interpret it, and transfer it to another system. Gateways are also called protocol converters and can operate at any network layer. Gateways are generally more complex than switch or router.
3. Router→ Network layer: A router is a device like a switch that routes data packets based on their IP addresses. Router is mainly a Network Layer device. Routers normally connect LANs and WANs together and have a dynamically updating routing table based on which they make decisions on routing the data packets. Router divide broadcast domains of hosts connected through it.
Bridge→ Data link layer: A bridge is a repeater, with add on functionality of filtering content by reading the MAC addresses of source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port, thus making it a 2 port device.
Inserting a '0' in user data stream to differentiate it with a flag
Inserting a '0' in flag stream to avoid ambiguity
Appending a nibble to the flag sequence
Appending a nibble to the user data stream
●The receiver knows how to detect and remove or disregard the stuffed bits.